Fixes and improvements for SerializationTest

The tests were order-dependent and flawed: test support classes
were used in multiple tests but each relied on it being possible
to detect static initialization of those classes. There was an
incorrect assertion.

This change splits out unique test support classes for those
that need them, adds more assertions and fixes the broken
assertion. Also tidies up some warnings.

Bug: 23031484
Change-Id: Ia3bb32dd1dbd02a74931604cae424d7e9312c76d
(cherry picked from commit 729d4ecafff8e6af5a71e4fecb2007917cbc2e2a)

1 files changed, 67 insertions, 37 deletions

diff --git a/luni/src/test/java/libcore/java/io/SerializationTest.java b/luni/src/test/java/libcore/java/io/SerializationTest.java
index 32bc402..03e7d94 100644
--- a/luni/src/test/java/libcore/java/io/SerializationTest.java
+++ b/luni/src/test/java/libcore/java/io/SerializationTest.java
@@ -49,7 +49,9 @@ public final class SerializationTest extends TestCase {
 
     static class FieldMadeTransient implements Serializable {
         private static final long serialVersionUID = 0L;
+        @SuppressWarnings("unused")
         private transient int transientInt;
+        @SuppressWarnings("unused")
         private int nonTransientInt;
     }
 
@@ -64,7 +66,7 @@ public final class SerializationTest extends TestCase {
                 + "374244669656c644d6164655374617469630000000000000000020001490009737461746963496e7"
                 + "47870000022b8";
         FieldMadeStatic deserialized = (FieldMadeStatic) SerializationTester.deserializeHex(s);
-        // The field data is simply ignored if it is static.
+        // The field data must be ignored if it is static.
         assertEquals(9999, deserialized.staticInt);
     }
 
@@ -74,73 +76,101 @@ public final class SerializationTest extends TestCase {
         private static int staticInt = 9999;
     }
 
+    public static boolean serializableContainer1InitializedFlag = false;
+    public static boolean unserializable1InitializedFlag = false;
+
+    public static class Unserializable1 {
+        static {
+            SerializationTest.unserializable1InitializedFlag = true;
+        }
+    }
+
+    static class SerializableContainer1 implements Serializable {
+        private static final long serialVersionUID = 0L;
+        private Unserializable1 unserializable = null;
+
+        static {
+            serializableContainer1InitializedFlag = true;
+        }
+    }
+
     // We can serialize an object that has an unserializable field providing it is null.
     public void testDeserializeNullUnserializableField() throws Exception {
         // This was created by creating a new SerializableContainer and not setting the
         // unserializable field. A canned serialized form is used so we can tell if the static
         // initializers were executed during deserialization.
-        // SerializationTester.serializeHex(new SerializableContainer());
-        String s = "aced0005737200376c6962636f72652e6a6176612e696f2e53657269616c697a6174696f6e54657"
-                + "3742453657269616c697a61626c65436f6e7461696e657200000000000000000200014c000e756e7"
-                + "3657269616c697a61626c657400334c6c6962636f72652f6a6176612f696f2f53657269616c697a6"
-                + "174696f6e546573742457617353657269616c697a61626c653b787070";
+        // SerializationTester.serializeHex(new SerializableContainer1());
+        String s = "aced0005737200386c6962636f72652e6a6176612e696f2e53657269616c697a6174696f6e54657"
+                  + "3742453657269616c697a61626c65436f6e7461696e65723100000000000000000200014c000e7"
+                  + "56e73657269616c697a61626c657400124c6a6176612f6c616e672f4f626a6563743b787070";
 
-        serializableContainerInitializedFlag = false;
-        wasSerializableInitializedFlag = false;
+        assertFalse(serializableContainer1InitializedFlag);
+        assertFalse(unserializable1InitializedFlag);
 
-        SerializableContainer sc = (SerializableContainer) SerializationTester.deserializeHex(s);
+        SerializableContainer1 sc = (SerializableContainer1) SerializationTester.deserializeHex(s);
         assertNull(sc.unserializable);
 
         // Confirm the container was initialized, but the class for the null field was not.
-        assertTrue(serializableContainerInitializedFlag);
-        assertFalse(wasSerializableInitializedFlag);
+        assertTrue(serializableContainer1InitializedFlag);
+        assertFalse(unserializable1InitializedFlag);
     }
 
-    public static boolean serializableContainerInitializedFlag = false;
+    static class Unserializable2 {
+    }
 
-    static class SerializableContainer implements Serializable {
+    static class HasUnserializableField implements Serializable {
         private static final long serialVersionUID = 0L;
-        private Object unserializable = null;
-
-        static {
-            serializableContainerInitializedFlag = true;
-        }
+        @SuppressWarnings("unused") // Required to make objects unserializable.
+        private Unserializable2 unserializable = new Unserializable2();
     }
 
     // We must not serialize an object that has a non-null unserializable field.
     public void testSerializeUnserializableField() throws Exception {
-        SerializableContainer sc = new SerializableContainer();
-        sc.unserializable = new WasSerializable();
+        HasUnserializableField uf = new HasUnserializableField();
         try {
-            SerializationTester.serializeHex(sc);
+            SerializationTester.serializeHex(uf);
             fail();
         } catch (NotSerializableException expected) {
         }
     }
 
+    public static boolean serializableContainer2InitializedFlag = false;
+
+    @SuppressWarnings("unused") // Required for deserialization test
+    static class SerializableContainer2 implements Serializable {
+        private static final long serialVersionUID = 0L;
+        private WasSerializable unserializable = null;
+
+        static {
+            serializableContainer2InitializedFlag = true;
+        }
+    }
+
     // It must not be possible to deserialize an object if a field is no longer serializable.
     public void testDeserializeUnserializableField() throws Exception {
-        // This was generated by creating a SerializableContainer and setting the unserializable
+        // This was generated by creating a SerializableContainer2 and setting the unserializable
         // field to a WasSerializable when it was still Serializable. A canned serialized form is
         // used so we can tell if the static initializers were executed during deserialization.
-        // SerializableContainer sc = new SerializableContainer();
+        // SerializableContainer2 sc = new SerializableContainer2();
         // sc.unserializable = new WasSerializable();
         // SerializationTester.serializeHex(sc);
-        String s = "aced0005737200376c6962636f72652e6a6176612e696f2e53657269616c697a6174696f6e54657"
-                + "3742453657269616c697a61626c65436f6e7461696e657200000000000000000200014c000e756e7"
-                + "3657269616c697a61626c657400124c6a6176612f6c616e672f4f626a6563743b7870737200316c6"
-                + "962636f72652e6a6176612e696f2e53657269616c697a6174696f6e5465737424576173536572696"
-                + "16c697a61626c65000000000000000002000149000169787000000000";
-
-        serializableContainerInitializedFlag = false;
-        wasSerializableInitializedFlag = false;
+        String s = "aced0005737200386c6962636f72652e6a6176612e696f2e53657269616c697a6174696f6e54657"
+                  + "3742453657269616c697a61626c65436f6e7461696e65723200000000000000000200014c000e7"
+                  + "56e73657269616c697a61626c657400334c6c6962636f72652f6a6176612f696f2f53657269616"
+                  + "c697a6174696f6e546573742457617353657269616c697a61626c653b7870737200316c6962636"
+                  + "f72652e6a6176612e696f2e53657269616c697a6174696f6e546573742457617353657269616c6"
+                  + "97a61626c65000000000000000002000149000169787000000000";
+
+        assertFalse(serializableContainer2InitializedFlag);
+        assertFalse(wasSerializableInitializedFlag);
         try {
             SerializationTester.deserializeHex(s);
             fail();
         } catch (InvalidClassException expected) {
         }
-        // Confirm neither the container nor the contained class was initialized.
-        assertFalse(serializableContainerInitializedFlag);
+        // The container class will be initialized to establish the serialVersionUID.
+        assertTrue(serializableContainer2InitializedFlag);
+        // Confirm the contained class was initialized.
         assertFalse(wasSerializableInitializedFlag);
     }
 
@@ -196,7 +226,7 @@ public final class SerializationTest extends TestCase {
                 + "e546573742457617353657269616c697a61626c65000000000000000002000149000169787000000"
                 + "000";
 
-        wasSerializableInitializedFlag = false;
+        assertFalse(wasSerializableInitializedFlag);
         try {
             SerializationTester.deserializeHex(s);
             fail();
@@ -239,7 +269,7 @@ public final class SerializationTest extends TestCase {
         final String s = "aced0005737200336c6962636f72652e6a6176612e696f2e53657269616c697a6174696f6"
                 + "e546573742457617345787465726e616c697a61626c6500000000000000000c0000787078";
 
-        wasExternalizableInitializedFlag = false;
+        assertFalse(wasExternalizableInitializedFlag);
         try {
             SerializationTester.deserializeHex(s);
             fail();
@@ -275,7 +305,7 @@ public final class SerializationTest extends TestCase {
                 + "e5465737424576173456e756d00000000000000001200007872000e6a6176612e6c616e672e456e7"
                 + "56d0000000000000000120000787074000556414c5545";
 
-        wasEnumInitializedFlag = false;
+        assertFalse(wasEnumInitializedFlag);
         try {
             SerializationTester.deserializeHex(s);
             fail();
@@ -309,7 +339,7 @@ public final class SerializationTest extends TestCase {
         final String s = "aced00057372002b6c6962636f72652e6a6176612e696f2e53657269616c697a6174696f6"
                 + "e54657374245761734f626a656374000000000000000002000149000169787000000000";
 
-        wasObjectInitializedFlag = false;
+        assertFalse(wasObjectInitializedFlag);
         try {
             SerializationTester.deserializeHex(s);
             fail();